The following abbreviations are used herein:
3GPP3rd Generation Partnership ProjectD2DDevice-to-Device CommunicationD2D-UE or DUECellular User equipment with direct communicationcapabilityeNodeBEvolved NodeBePDCCHenhanced Physical Downlink Control ChannelFDDFrequency Division DuplexLTELong Term EvolutionMAC PDUMedium Access Control Protocol Data UnitPDCCHPhysical Downlink Control ChannelRBResource BlockRXReceiveSAScheduling AssignmentSIBSystem Information BroadcastTBTransport BlockTDDTime Division DuplexT-RPTTime Resource Pattern of TransmissionTXTransmitUEUser Equipment
Recent advancements in the field of cellular communication include providing support for direct communication between mobile devices in the licensed spectrum. This is widely known as device-to-device (D2D) communication. This has largely been motivated by the popularity of proximity based services steered by social networking applications as well as public safety. D2D communication has several advantages including, but not limited to, improving overall spectral efficiency, improving local coverage, facilitating traffic offloading from a cellular network, and enabling various types of new services and applications.
The 3rd Generation Partnership Project (3GPP) has been working towards including D2D communication feature as an overlay to its existing Long Term Evolution (LTE) cellular network. 3GPP has a target of providing the major functionality needed to support public safety communication in to its upcoming Release 12 standards and beyond. Under this goal, two functionalities, namely, broadcast communication in and out-of network coverage, and device discovery under network coverage, have been prioritised. Current progress on D2D broadcast communication includes the definition of two communication modes, namely Mode-1 and Mode-2.
In Mode-1 broadcast communication, an eNodeB or rel-10 relay node schedules the exact resources used by a UE to transmit direct data and direct control information. In particular, the eNodeB or Rel-10 relay allocates resources to a D2D transmitter for D2D control information or scheduling assignment (SA) transmission and corresponding D2D Data transmission using PDCCH or ePDCCH. This enables collision free multi-user access.
In contrast, in Mode-2 communication, a D2D-UE selects resources from common resource pools to transmit direct data and direct control information or SA. Mode-2 communication can be operated under network coverage or out-of-network coverage. However, in both scenarios, resource selection for SA and data transmission is performed by the UE without a central coordination. Thus, D2D-UEs performing mode-2 communication have to contend with each other to acquire resources in resource pool for SA and corresponding data transmission, which creates a contention-based multiple access environment with collisions for mode-2 communication.
According to the current progress of 3GPP on resource allocation for mode-2 communication, it is envisioned that the resource pools for SA and data transmission will be pre-configured or semi-statistically allocated. The D2D-UEs may follow a time-domain transmission pattern (TX-RX pattern), or a so called time resource pattern of transmission (T-RPT), within the resource pools to transmit SA and associating data transport blocks (TBs), and repetitions thereof. The objective of TX-RX patterns or T-RPT is to minimise the half-duplex constraint and minimise in-band emission while enabling the receiver combining to improve detection performance. However, the design of the resource pool configuration, channel structure within resource pools and TX-RX patterns is complex and has not been defined.
Channel sensing based resource selection and random resource selection have been considered as two candidates for resource selection in mode-2 communication. However, implementation of channel sensing based resource selection in a multiple channel environment is very complex. It is therefore envisioned that a random resource selection will be the baseline for mode-2 broadcast communication. However, the design of SA and data transmission using random resource selection is complex and has not been defined.
Accordingly, while the design of the resource pool configuration has been considered in 3GPP, there are currently no suitable resource selection methods for mode-2 communication. Accordingly, there is a need for an improved method and system for configuring D2D communication.
It will be clearly understood that, if a prior art publication is referred to herein, this reference does not constitute an admission that the publication forms part of the common general knowledge in the art in Australia or in any other country.